This driver allows the user to control bit 8 of the built-in RS-232 port in Emulation Mode. Bit 8 is used by some printers to select expanded or normal print mode or to enable alternate or graphics character sets. DOS 3.2 or DOS 3.3 is required to use this routine. Both the Serial Card Emulation and the Communications Card Emulation are supported.
SOFTWARE ENTRY
Boot a DOS diskette and enter the monitor with CALL -155 and type
3B0:A9 07
:20 95 FE
:A9 80
:20 ED FD
:A9 C5
:85 36
:A9 03
:85 37
:4C EA 03
:29 7F
:0D CD 03
:4C 07 C7
:80
To check your typing, type
3B0L
and compare your listing to the one below.
03B0- A9 07 LDA #$07
03B2- 20 95 FE JSR $FE95
03B5- A9 80 LDA #$80
03B7- 20 ED FD JSR $FDED
03BA- A9 C5 LDA #$C5
03BC- 85 36 STA $36
03BE- A9 03 LDA #$03
03C0- 85 37 STA $37
03C2- 4C EA 03 JMP $03EA
03C5- 29 7F AND #$7F
03C7- 0D CD 03 ORA $03CD
03CA- 4C 07 C7 JMP $C707
03CD- 80 ???
Now return to Basic with 3D0G
SAVING THE PROGRAM TO DISK:
Save the driver to disk by typing
BSAVE SERIAL DRIVER, A$3B0, L$1E
USING THE PRINTER:
The driver should be in memory before you want to use the printer. You must load the driver and initialize the interface.
From command mode type
BLOAD SERIAL DRIVER
CALL 944
This may be done from a program by entering
100 PRINT D$;"BLOAD SERIAL DRIVER" : CALL 944
assuming that D$ contains a CTRL-D.
If you want to switch back to the video monitor for output type
PR#0
or in a program enter
200 PRINT D$;"PR#0"
Then to reconnect the printer, all that is required is
CALL 954
or from a program
300 CALL 954
SETTING THE PRINT MODES:
To set normal print mode POKE 973,0
To set expanded print mode POKE 973,128